1. Field
This disclosure relates generally to circuits, and more specifically, to a switching circuit having a driver for providing a substantially linear voltage transition.
2. Related Art
Switching circuits, such as high-side switches and low-side switches, are used for supplying power to motors, lights, and other devices. Switching circuits are commonly used in automotive applications. Various transistor types may be used to implement a switching circuit. A metal-oxide semiconductor (MOS) transistor is one such transistor type.
Generally, a depletion capacitance, also called junction capacitance, is associated with a MOS transistor. The depletion capacitance of a MOS transistor is variable with voltage, so that for a given gate current, the output voltage of the transistor will ramp up in a non-linear manner when the transistor is transitioning from an “off” state to a fully “on” state. The transition may start out at a high ramp rate that lessens as the output voltage increases. The lower ramp up rate can cause the transition from the off state to the fully on state to require a relatively long period of time. The relatively long transition period may be undesirable for some applications. Also, the relatively long transition period may result in increased power dissipation. However, if the transistor is biased with a relatively higher gate current to increase the ramp up rate of the output voltage and to shorten turn on time, the higher ramp up rate may induce electromagnetic interference (EMI) that is undesirable in many applications.
Therefore, what is needed is a switching circuit that solves the above problems.